


All Jim Wanted To Know Was What Spock's Dick Looked Like (And Look Where That Got Him)

by bubblegumboi (Hawkbringer)



Series: Hawkbringer's Greatest Hits [8]
Category: Star Trek: Alternate Original Series (Movies), Star Trek: The Original Series
Genre: Alien Biology, Anal Sex, Anatomical Accuracy, Bottom James T. Kirk, Buckets of cum, Changing Tenses, Enema (mention), Explicit Sexual Content, Extreme Insertion, Fanon Vulcan Terminology, Fisting, Id Fic, M/M, Our Vulcans Are Different, Plot What Plot/Porn Without Plot, Tooth-Rotting Fluff, Top Spock, Watersports, and kirk is mega into it, basically spock's penis is insanely long, bordering on body horror, disturbingly lovingly detailed descriptions of the human colon, expanding penis, whoops
Language: English
Status: Completed
Published: 2019-03-26
Updated: 2019-03-26
Packaged: 2019-12-18 11:46:07
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 6,443
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18249191
Author URL: https://archiveofourown.org/users/Hawkbringer/pseuds/bubblegumboi
Summary: Spock hasn't seen a human penis? Well, Jim's never seen a Vulcan one! This is the perfect opportunity for cross-cultural exchange! Of course, Jim's always horny, so it gets very sexual, very quickly. (Mind the tags) (written 2012)





	1. Chapter 1

**Author's Note:**

> Original author's note from 2012: okay, so I had this crazy idea for funky anatomy for vulcan penis. The females of course don't ovulate the way humans do, so they'd either have a few months of the year where they're in heat, and that's one theory about pon farr, but prolly not. They'd be the illogical, afflicted ones in that case. Maybe it's more like cats, where there's some amount of physical stimulation which results in ovulation, and vulcan semen is hardier, to wait that long for an egg to fertilize. also, retractable penis. Wait for it....
> 
> \---
> 
> Spock's dick behaves like a sort of expanding prehensile tentacle, and he produces a ridiculous amount of sex-fluids for a desert-dwelling species... But Jim's human anatomy is carefully adhered to... It's porn, it doesn't have to make sense. Both the tense and the characterization keep wobbling from one side to the other, so I'll throw this in both TOS and AOS, it works for either. Or both. Or some mirror-universe AU where everything is extra-sexy instead of extra-evil. >:) 
> 
> Hope you enjoy!

Spock begins. "Your shape is like a cylinder, with the tip the shape of a sprouting mushroom." 

Jim goes, "Yeah, that's pretty accurate. Bout 5 inches long on average. 'Cross the species."

"It does not change shape?"

"Well, it goes from, uh, flaccid, I guess, to hard, and really the only change is in length, and girth. When it's not hard, it's still the same shape, a cylinder, like you said, but the head is much less noticeable. Some of us also have foreskin, which covers the head all the time unless it's hard. Some men get that chopped off for cleanliness reasons, I guess. Or cosmetic or religious. I never really understood the whole circumcision thing. I didn't get it. Didn't need to. I'm fine and functioning just the way I was born!"

"I am glad we are in agreement on that issue, Jim." Kirk smiles as his cheeks blush. He eagerly leans forward to touch Spock's shoulder. 

"How bout Vulcan shapes? What do _you_ look like, Mr. Spock?"

He takes a deep breath. "When erect, my penis is cylindrical, as your is, but with no pronounced head. The tip simply tapers into a cone shape. Flaccid, it is not visible. Retracted. It is enclosed in a pouch that resembles the human scrotum, but that can handle much rougher treatment. The human scrotum, from what I can tell, is very sensitive, correct?" 

Jim nods emphatically, his eyes going big. "Yours isn't?"

"I am not in possession of a scrotum, Jim. The closest translation is holding-sheath, for the penis itself is far more sensitive than that of human males. Anatomical studies comparing nerve clusterings have discovered that the Vulcan penis is far closer to a human clitoris in number of nerves, and, accordingly, sensitivity." 

Kirk whistles with appreciation. Then he thinks of something. "Where do you guys keep your balls? Erm, testes?"

"They are internal, actually. A rather more logical arrangement, in my view." He says that just to get Kirk's attempted-raised-eyebrow expression. Then he turns around and lifts the back of his shirts up slightly, places his fingers very gently at the top of the small of his back. "They are called _chenesi_ , singular or plural. Vulcans can function reproductively with only one, as humans can. You see the small raised patches of skin on either side of the spine?" 

"I can see them. That's it?"

"Yes. _Very_ sensitive," Spock informs him dryly, dropping his shirt hems and turning back around to face Kirk. "Being kicked in the back would be as devastating to a Vulcan as a kick to the genitals for a human." 

Jim whistles again, eyebrows knitting in sympathy, remembering some of his own experiences with being kicked in the groin. Then he had a sudden thought, his eyebrows jumping, though Spock, with his back to Jim, couldn't see it. "I guess that brings new meaning to the phrase 'watch my back,' eh, Mr Spock?" 

He blinks impassively, but a hint of green washes over his cheeks and Kirk knew he had ammo for the next time... Shaking his head to get visions of touching Spock's back _on the bridge_ out of his mind, he continues, "So your, ahh, sheath isn't as sensitive as a human scrotum, but your... equipment itself is? More so than a human male's." Spock nodded again. 

Kirk swallowed nervously, then made his proposal. "May I... mmm. May I... see it?" 

Spock quirked one eyebrow and Kirk had to stifle his giggle at the so-very-familiar expression. 

"As I am not physically aroused at the moment, there is nothing _to_ see," he reminded Kirk, who suddenly thought of something and was immediately distracted. 

"Hmm-- Wait! how do you, uhh... relieve yourself? In the bathroom?" Spock tilted his head. 

"How do you?" he countered. 

_Fair play,_ Jim considered. "With human males, since our, uh..." 

"Penis," Spock supplied impassively. 

Jim giggled, the very image of a 5 year old boy. "...Is right out in the open, we just... I just.. unzip my pants, pull down my underwear, and... hold it. I try to aim for the toilet." His cheeks were so hot, he could have forgiven Spock for wondering if he had a fever. He forced his brain to switch over to clinical anatomical mode to try and take the embarrassment out of it. "The little hole on the head of the penis is the very end of the urethra, the small tube that runs through the inside of the penis and goes up into the bladder. That same tube expels... ejaculate, in a sexual context. I think there's a little off-switch somewhere.... when a man is aroused, or nervous, the valve between the bladder and the urethra closes and he can't pee. The urethra also has a connection to the sexual organs which curl around the bladder and go to the testes... Man, I didn't realize I knew as much about that as I did!" 

Kirk felt his cheeks were still hot, but Spock was nodding seriously as if absorbing the new information, so Kirk considered it mission accomplished. 

"The Vulcan seminal and urinary delivery system is much similar. Of course, given our superior control over our bodily functions, it is more of a mental matter to decide whether to urinate or not." Jim rolled his eyes and one side of Spock's mouth quirked up. "However, we do not have this single tube within the penis that humans do. The urethra does connect to the bladder, and the testes, with several additional small glands along the length of the vas defrens that aid in the production of seminal fluid from simple sperm." 

Jim nodded. "Humans have that too. The main one's the prostate, I think." 

Spock's eyes glittered dangerously. "Yes, accessible via digital probing of the rectum, am I correct? Capable of producing intense pleasure when stimulated?" 

Kirk gulped again, and shifted in his seat. "I... suppose so. I've never felt... intense pleasure from any of McCoy's digital rectal massages.. Which he has to do in the line of duty, I assure you! It's part of every man's physical," he rushed to assure Spock, whose eyes had narrowed dramatically. "So, you can have the honor of making it an erogenous zone for me, instead of just a medical... examination... thing." He dropped his gaze, feeling about 3 years old, kicking at the sidewalk, embarrassed at being found guilty, thought he wasn't sure of what. 

Spock's gentle fingers beneath his chin and the Vulcan's soft gaze calmed him. "I shall hold you to that, James Tiberius Kirk." Kirk swallowed hard again, trying to wet his dry mouth. He'd been doing that a lot this evening, and only now realized that it wasn't from nervousness, exactly, but anticipation. 

"As I was saying," Spock continued, now that he had Kirk's attention back on him, and off McCoy, even mentally, "The Vulcan penis... _my_ penis.... does not have a single tube running the length of it. There are several pores along the entire length - and know this Jim - when erect, the length can and will expand to fill any given orifice -" Kirk shivered and his eyes fluttered closed briefly, unable to deny the very visceral reaction to the idea of Spock's length _filling_ him. "- And several different types of fluid are excreted through these pores. Urine, when no sexual excitation is present, lubrication which doubles as a protective coating when arousal begins, and seminal fluid at the conclusion of a sexual act." 

Kirk shifted in his chair again and barely managed to get out a vague sound of agreement before Spock was standing suddenly, and ushered Kirk into the bathroom they shared, situated between their quarters. 

"As it seems inevitable from your rising color and obvious sexual excitation, I believe now would be an excellent time to relieve our respective bladders and simultaneously provide mutual demonstrations as a proof of concept." 

As he spoke, Spock had situated himself in front of the toilet, standing facing it the same way Jim would, and had unbuttoned and unzipped his slacks and eased them down to his upper thighs. Jim couldn't see his not-ball-sac - holding-sheath - from this angle, and it took him a second to catch up. "You... you want me to look at you while you pee?"

Spock turned his face to him with a very frank and slightly ironic expression. "Why, yes, Jim, that is a wonderful idea. And I will, of course, reciprocate."

Slightly dazed, Jim faintly muttered, "Of course..." as he had to Garth of Izar, once, many solar months ago.

But, of course, curiosity got the better of one James T-for-Tomcat Kirk, and he did shuffle, slightly guiltily, around to Spock's side, getting a better view of the wrinkled and furry pouch that looked, for all the world, just like a human scrotum, complete with scar-like bisecting line. 

Spock slid one hand underneath it as Jim watched, lifting it away from his underwear and massaging it deftly. He exhaled purposefully through his nose and Jim's eyes darted from his friend's closed eyes to the now-swelling pouch he held quite casually in his hand. Spock shifted his hips, leaning one side forward and then the other and Jim watched with rapidly-widening eyes as the holding-sheath swelled to the size of an apple, an orange, and before it truly crossed the line into grapefruit territory, the bisecting line bulged and twitched. 

Jim held his breath. It looked like someone was running a finger up the _inside_ of his friend's impressively-versatile genitals. The stroking motion happened again, more forcefully, and Spock exhaled purposefully again. Then the pouch _opened_ along the natural bisecting line and what looked like the tapered end of large tree root poked out. _That's his cock!_ Jim shouted jubilantly in his head. About an inch long, far skinnier than a finger, the prehensile member twitched in the open air, lovingly stroking the sides of the slit that had opened for it. Spock canted his hips with all the familiarity and intent of a man taking careful aim, then he just about squeezed the life out of the sac in his hand. 

Jim tried to keep his gasp behind his lips, as sympathetic pain shot through his groin and left it throbbing. He placed one hand over his own groin, without conscious thought, and startled at finding himself half-hard. 

Piss streamed from the tip of Spock's green-tinged tree-root dick, the way water would run off Jim's in the shower. Trying to be scientific, Jim contemplated how the pouch must first have filled with urine, and then when it was full, Spock released it by opening the line that bisected the pouch from the inside, _with his dick._ Jim really wished his dick could be as awesome as that. 

Then Spock seemed to manually empty the pouch by squeezing it, necessarily or maybe not, and trusted the slightly-extended tip of his penis to guide the way for the urine to fall. As the pouch deflated back to its normal size, Spock gave it a few more squeezes and twitched the end of his penis in a kind of kegel-exercise, to make sure the last drops had left. Then he absentmindedly molded the elastic flesh up around the end of his penis and rolled it with his fingers until it too shrank back down to size and out of sight.

Spock then opened his eyes and turned to Jim, one eyebrow raised as if to say, "Satisfactory?"

"Goddamn. Wow," was Jim's only eloquent response. That just got him an eyebrow hiked higher. Jim hoarsely added, "I wish the way I _went_ was that awesome." Spock's eyes crinkled slightly at the corners and Jim realized, but didn't even care, that he was being silently laughed at.

Jim searched his friend's eyes, confident he wouldn't find any true malice in their depths. He was rewarded for his intense scrutiny with a deeper register than normal to Spock's voice when he gently goaded, "It is your turn, Jim." 

Jim blinked repeatedly, looked away, and gulped. "Right. Uh. My turn. Yes." He shuffled briefly for space in front of the toilet as Spock rezipped his fly and stood aside.

Jim took a deep breath and closed his eyes, knocking the toilet with his shins in the dark, to make sure he knew where it was going to be five minutes from now. He reminded himself of how nervous he felt, which succeeded in shriveling his cock down to a size where he could comfortably go, but also clamped down on his bladder, ensuring that he couldn't. 

_Damn shy dick,_ he muttered to himself in his head as he undid his pants and gingerly shoved the bulk of his underwear down past his dick, lifting his sac up and over the clothing. 

He breathed deeply again and purposefully thought of waterfalls, calming nature sounds, ocean waves... all this succeeded in relaxing him down to the point where, when he took his dick in hand and tightened the surrounding muscles, as they slackened, a stream of urine happily made its way out of his bladder. He opened his eyes in time to aim just a little better - and purposefully did not pay /any/ attention to anything in his peripheral vision. As the stream slowed to a drip, Jim squeezed his penis gently, and shook it, waving it up and down and back and forth, just a little, to make sure he was in the clear. He flushed the toilet then, and turned to Spock as he put himself back in his pants. 

"Well? Whaddid ya think?" he quiered lightly to hide his nerves.

"Fascinating." 

Finally, Jim allowed himself to laugh.


	2. Chapter 2

Later, as they sat mostly naked on Jim's bed, Jim had gotten to the point of exploring Spock's pouch, touching it, lifting it. (He'd been relieved to discover that Vulcans excreted solid waste in the same way humans did - he had an asshole and perineum and all the wonderful little nerve bundles that went along with that.) 

"Squeeze it, Jim. It can take much more stimulation without pain than can your own." 

So he did. He was surprised to feel a slight hardness within it, on the opposite side from the beautifully delicate slit-opening. He then felt like smacking his forehead, as that was probably the root of his first officer's cock. 

"I wonder what would happen if I did this," he murmured out loud, gathering the loose flesh around the thick protrusion and jerking it briskly. He was rewarded with Spock's first out-of-control gasp of the evening. 

"Ah! Oh, Jim..." 

"Good?" his partner asked a little breathlessly. 

"Yes, oh... s-so good. Please, continue!" 

Smirking just a teeny bit, Jim did so, finding the slow elongation of the hardness, its covered swelling and pulsing, to be far more erotic than his own simplistic on-off switch as well as being... 'fascinating,' to coin a phrase. 

"How big can you make it inside there without letting it out?" he asked breathlessly as, scant minutes later, the pouch was going taut beneath his fingers, the penis within it coiled up like a snake, and wriggling impatiently. 

"I... do not know," Spock panted, making fists in the sheets beside him as Jim placed his lips over the still-closed pouch and mouthed at the tip. Spock shouted something unintelligible and the tip of his dick 'licked' up the inside of the pouch again, as it had in the bathroom when it wanted to come out. 

"Tsk, tsk, tsk," Jim chucked disapprovingly. "Having trouble controlling our bodily reactions, are we?" He smiled up at Spock and let all of his joy and beaming expression bleed into his voice.

"Only you..." Spock gasped, heaving great big lungfuls of air and fighting to control the quivering of his stomach and the urgency in his loins, "Only you.. can.. drive me... to such... extremes." 

Jim's teasing expression melted into pure gratitude and he came to a decision then, one that would have exponentially-increasing consequences over time, and yet, one of the easiest decisions he had ever had to make.

"I want you to penetrate me. Anally," he declared, enunciating and adding the adverb so that there could be no misunderstanding between them. "Now. Preferably sooner." 

Spock whined, squeezing his eyes shut tighter and in the sac between his hands, Jim felt what little slack the coiled penis had left in the skin was suddenly taken up by a flood of fluid, pulsing seemingly from the penis itself. _The multiple pores he was talking about.... kind of like a watering hose._ Jim pictured the long flattened tube, studded with holes every few inches, that his mother would use on the small flowerbeds around their house. 

Spock's pouch quivered as the man himself moaned, more aroused, it seemed, the more fluid flooded out of him. _So this isn't ejaculation,_ Jim hastily calculated in his mind. _This must be the protecting-lubricating fluid he talked about earlier. Oh, joy! He /can/ penetrate me! I can't wait!_ Impatient as ever, Jim massaged the stiffening, painfully tight pouch more fully, feeling the weight of the fluid roll back and forth, wanting to coat Spock's entire coiled penis, and praying that the mess of fluids he was about to receive would make it easier for Spock to get his cock inside. 

"Jim," Spock called hoarsely, and Jim immediately slowed his hands, climbing on top of Spock and sitting on his upper thighs, the pouch still before him, moss-green and fuzzy and round as a honeydew. 

"Yes, Spock? What is it?" Jim let his purple-headed penis dribble some of its happy fluid down onto Spock's filled-to-the-brim pouch. 

That action, he would later decide, was the straw that broke the camel's back. 

At the sensation of wetness on the _outside_ of his body, (which translated into 'aroused body ready for sex nearby' in his instinct-ruled hindbrain), Spock gave one last sobbing cry, then rocketed upward from where he lay flat on his back. He seized Jim at the narrowest part of his waist and dragged his captain beneath him as he mounted Jim, their faces still very close. 

"Would you prefer penetration like this, or on your knees?" he hissed with a voice like gravel into Jim's ear. He shivered, hard. 

"Oh, put me on my knees, yes. Please! I know I can take more of you in that way," he begged, pleading and babbling excitedly. 

"As you wish," Spock hissed, and flipped him with nonchalant ease. 

Shocked by the abrupt display of strength, Jim forgot to brace himself for a moment and just laid there, flat on his stomach. Spock growled impatiently and pulled his hips up for him, leaving Jim's shoulders against the bed. 

Jim turned his head to the side and barely caught the glint of a feral and dangerous and _motivated_ Vulcan sparkling in the eyes of his First Officer, then Spock knelt in the space between Jim's spread thighs and bent himself in half and settled his chin over Jim's other shoulder. 

Now Jim could hear him, feel him, smell him... but not see him. And that suited Spock just fine.

"You asked for anal penetration," Spock stated, just loudly enough for Jim to hear. Jim nodded, helplessly aroused, his mouth open and his eyes closed. His kegel muscles, including his anus, convulsed and eased at the sudden sensation of Spock's hot and tight-skinned pouch nudging at the crease of his backside. "You are going to get it," Spock promised, as the white-green tip of his cock licked up the inside of his pouch once again, and this time met no mental resistance. "In _spades_ ," he finished with a growl as the wet and writing tip of his penis opened the slit of his sac in its eagerness. 

Immediately upon touching the hot and quivering flesh of another being, the tip of Spock's penis twirled out of its pouch, following the coiled pattern it had taken up inside, forcing a moan past Spock's lips as the sensitive lips of the slit pulsed at the friction. Probing, as it had evolved to do, at the hot and sweaty flesh before it, the tip of Spock's penis quickly found the darker, hotter, tighter indentation in Jim's flesh and with a cry of triumph, Spock's penis forced its well-lubed way inside. 

Oh, Jim was better than his word! He was clean inside, empty for miles, had possibly taken an enema for precisely this purpose. And as yielding as he was, the slick lubrication was damn useful too, and Spock pulled Jim's hips closer to his, lining up the lips of his spread slit and Jim's asshole, and pressed them together tight, as five inches of wet Vulcan passion slid deep inside of him in one single thrust. 

Jim moaned, so very aroused, by the hot, wet warmth coating the insides of his channel, by the pulsing, thrusting, twitching of the almost-sentient, prehensile cock inside of him, by the long-fingered hands clamped bruise-giving hard onto his hips. He whimpered, moaned, sighed, squirmed and begged Spock to take his dick in his hand, or let him shift to touch it himself. 

"No," Spock exhaled into his ear, causing another delicious shudder through Jim's abdomen. "You will last longer if I do not." 

"Tha-ahh!-that's true... Oh, dear god, Spock, tell your dick to keep touching me right there, hard right up against there, that's my prostate, that's... Aaahhh-hahaha _ha!!_ Soooo good!" Jim moaned as he shuddered. Spock's lips curled back in a dangerously feral grin, and he wondered if perhaps Jim could take more than the six inches he was plundering him with at the moment. Well, first, he would need more fluids pumped inside... So Spock shifted his body slightly upwards, moving his hands to the tops of Jim's thighs and pulling them upwards too. 

Braced on his toes now, and held half-horizontal by Spock's super-human strength, Jim paid close attention as his favorite new toy - Spock's cock - disappeared from his ass and the Vulcan commanding it peeled his body off of Jim's. Half-afraid he was about to be left high and dry, Jim drew breath to protest, but his whine was cut off at the source as a scream built in the back of his throat instead. 

Retracting his penis, tensing his abdomen, and rolling back his head, Spock had purposefully spread his slit wide and simultaneously plunged his cock back inside Kirk, using the speed of the forceful reentry to pump Jim's ass full of the heavy, slick lube he had only barely used for his first penetration. 

His swollen sac half-empty now, but the organ still leaking into his partner's channel, Spock groaned with satisfaction and laid his head down on Kirk's shoulder again. "I want you to swallow me. Bring all that fluid up, up, deep inside of you. Swallow me, with the internal muscles you even now clamp around my penis." 

Heaving for breath beneath Spock's weight and breathless from his scream, Jim only nodded as he gulped deep lungfuls of air, not at all cognizant of how completely their situations had reversed from barely fifteen minutes ago. 

Trying to coordinate at least some muscle movement, Jim half-heartedly twitched his hole closed, though it opened greedily barely a second later. 

"Yesss," Spock breathed into his ear, "Swallow me, just like that, James." Spurred on by Spock's encouragement, and the tiny happy moans he could get his first to make, Jim twitched his hole closed harder, and held it, and worked at retaining all the fluid Spock had pumped into him. Suddenly, it seemed to work, for the sphincter at the start of his rectum had twitched open of its own accord, and Spock's penis nudged into this new avenue of access. Sadly, it shrank closed in fear not two seconds later, but Spock kept up massaging at the area and very shortly, it opened again. This time, Spock was ready for it, and prodded his penis forward, holding the hole open and sliding past anyway as it tried to close around him, as Jim groaned in surprise beneath him.

Nothing had ever touched him this deeply, nothing he had ever taken pleasure from, anyway, nothing that had entered him from behind, driving pleasure before it as it plundered. Spock's penis was so amazing... Jim sighed in pure contentment as the girth of the member inside of him expanded slowly, widening his asshole and stretching the second internal sphincter. He kept twitching both of them closed around Spock's member at infrequent intervals, just to keep the Vulcan on his toes. 

Utterly lax with pleasure, Jim just smiled like a loon and shifted slightly beneath Spock as the Vulcan's penis plundered ever deeper.

He encountered a turn not long after breaching the second sphincter, and Spock's penis was easily able to accommodate that - after all, it had writhed inside his pouch, curled up like a slinky, ready to spring into motion at the slightest mental command. 

Twisting and turning was something Spock's penis did naturally, so it was quite at home exploring the warm, soft, clinging walls of Kirk's sigmoid colon. Encountering another turn made Spock cognizant of the need for more lubrication. Not wishing to injure Kirk, which he might do if he pulled out abruptly with his penis so far up inside his ass, Spock simply went still for a moment, concentrating on the requisite organs for production, and ordered them into brief but frenzied overload. 

Inside Jim, Spock's penis began pulsing, twitching, vibrating, and demonstrating the licking behavior Jim had observed earlier, now re-enacted inside his body. He stirred slightly, attempting to raise his head off the pillow of his arms, and made a questioning sound. Spock shushed him with many small kisses to his ear and neck and cheek, softly explaining his plan to Jim as his fluid-filled penis began to ooze lubrication into Jim's hungry ass. 

"I wish to penetrate you more deeply, _ashayam_. And I can do it - I do not feel that my penis has even yet reached its maximum extension. You simply require more lubrication. I have stilled my motions to concentrate on producing it. There, do you feel? The wetness seeping out into you, expanding the girth of your bowels? You will not be so uncomfortably full for long, James - the walls of your colon will absorb my fluids, hungry as you are for anything of mine to keep within you as your own." 

Jim moaned, let his head fall back onto the bed, squirming his hips against Spock's. Briefly contemplating the feeling of being full of Spock's lubricating fluid, produced just for him, Jim concluded that while the fullness was wonderful, if Spock was truthful, and more of the Vulcan could fit itself as painlessly into his body, Jim was eager to accept him. He'd said, earlier, hadn't he? That his penis could grow, as long and as thick as the sheath it was placed within? Jim moaned and eagerly rocked his hips back against Spock. 

The Vulcan chuckled. "Ready for more, my eager little one?" 

Jim moaned at the sound of Spock's voice, managing to form words this time. "Yeah... not little, though! Takin' your big cock... I'm huge! Fuck that big thing into me, see how much I can take, how big I can get. C'mon, c'mon. Wanna see, wanna find your limit. Fuck it so far into me... till I can't...take...any more!" Passion twisting the Captain's already-flushed features, he cried out and spasmed around Spock's suddenly, eagerly, inflating cock. 

Seeing the immediate and drastic effect that girth-expansion had on his lover, Spock took a few deep breaths and deflated his girth, focusing on tunneling deeper into Kirk's ass, more relaxed now, and flooded with pH-appropriate lubricant. Moaning himself as he let his prehensile member press forward in inch-worm-like gathering and relaxing forward contractions, Spock's pleasure at stretching his own boundaries doubled as Kirk's spiked, every time Spock's dick pulsed another lazy burst of fluid, or twisted inside of him like a corkscrew, or twitched, repeating the licking motion that Kirk seemed so enamored with earlier. 

And Spock discovered as his penis lengthened and filled and acquainted itself with every intimate detail of his Captain's lower intestinal tract, that Kirk was most fond of the licking. His pleasure spiked through his skin, igniting Spock's, every time the Vulcan tilted his hips downward, then up, and his cock copied the motion, sending a wave rolling through Kirk's very appreciative ass. 

Slowing his exploratory motions to prepare for one last pulse of lubrication, Spock took the time to run his hands over the overheated and sweating form of his captain, who had remained on his knees, with his shoulders on the bed, for the entire penetrative exploration. Jim hummed with sleepy pleasure at the touch, used to much, much, rougher treatment from this Vulcan. 

"Jim?" Spock quieried softly. "Are you awake?" Jim chuckled at the question, but it was with only half his usual vehemence. He was clearly sleepy, but indeed conscious. "I believe I am nearing full extension. How full do you feel?" 

Jim murmured very groggily, giving every appearance of someone who had just woken up from a nap, of all things. 

"Uhhhmmm... twitch the tip again, lemme see." Spock did so, rolling it backward and flicking it against Kirk's inner walls in a very passable imitation of the flick on the shoulder or back of the head he had occasionally seen McCoy give to Kirk when he was being a smartass. 

"Hey!" Jim exclaimed, jolting, then chuckling, apparently drawing the correct conclusion of the meaning of the flicking. "You're, let's see," he murmured, the sleep gone from his voice, as Spock had hoped, "You're just past the top of the descending colon. So full extension should take you to about the middle of the transverse colon?"

"You are... okay, with that?" 

"O' course! I did have a very thorough enema before I came here. Didn't want any nasty surprises on your dick when you pulled out, did you?"

"I...Yes. No. I am... touched by your thoughtfulness."

Kirk grunted, waved a hand over his left ear, not facing Spock. "Yeah, yeah, you're welcome, you snake-charmer." He then turned his head slightly over his shoulder and gave a smoldering smile. "So, you overly-romantic sop, you. Are you ready to fill your captain up with your highly-superior Vulcan semen?"

"I am quite ready, Jim," he intoned very seriously, which startled a guffaw out of Jim. 

Spock was curiously pleased to find that, so close to full extension, he could literally feel Kirk's laughter in his penis, as the vibrations from his diaphragm transmitted themselves into the large intestine just below.

"Let's get this show on the road," Kirk whispered back to him. "But, since we're so close, could you... hold my cock? Jerk it a little bit for me? I want to come too, you know."

"I would not let you suffer like that, _ashayam_." Spock placed an affectionate kiss beneath Kirk's ear and curled one hand easily around Jim's hardness, which had subsided somewhat during his semi-nap. 

A contented hum was all the response Kirk gave to Spock's grip and the Vulcan slowly began to work his hand over Kirk's erection as he shifted his own hips in preparation for one last lubrication-burst.

"Prepare yourself," Spock warned him, "My penis grows large within you."

"Yeah... yeah, I can feel it. Yeah, so big, make it bigger, S-Spock! Ooohhh!" The exclamation that spewed from Kirk's lips began as simple surprise, then climbed up the octave scale to end in a high-pitched shout. 

In time with his last forceful burst of lubricating fluid, which caused Spock's penis to quiver along its entire length, Spock forced himself to full extension, which caused the girth not only to swell, but the entire organ to slide deeper into Kirk's passage, propelled by the last 4 inches that had been sulking behind the lips of Spock's holding-sheath. The movement of such a long object against so many square inches of sensitive internal walls caused Kirk's entire abdomen to shiver and clench, which Spock did not object to, himself.

Spock's breath began to leave him in little puffs of air, huffed over Kirk's exposed ear, ruffling his hair. "I am very close, Jim. Soon I shall ejaculate within you, and you will be flooded, utterly filled with my semen. Is this sequence of events agreeable to you?"

"Damn Vulcan!" Kirk hoarsely gritted out past clenched teeth. He was grabbing at Spock's ass, his back, his side, whatever he could reach of the Vulcan in an attempt to stimulate him further, inflame him into non-control. "Fuck yes, I want your cock! Want you semen, cum, whatever the fuck you call it! Just fucking put it _in_ me!" he growled. 

Spock huffed out the barest of laughs at his mate's impatience. "You will have more within you than you may, perhaps, be able to retain, my arrogant human."

"You..sayin'..." Kirk panted, shifting his hips to gather more friction from Spock's lazy, too-loose jerking of his cock, "Your cum... gonna... overflow me?" 

"Grammatically...nggh...incorrect, but...Hah!.... roughly... accurate, James." Kirk was not the only one having trouble articulating. At full extension, the Vulcan penis was designed to blow its load very quickly and then retreat. Holding it extended, and holding himself back from the very precipice of orgasm was taking up a large portion of Spock's mental energy.

Spock fell silent, then, and Jim thought to himself, _Here it comes!_ and barely had time to groan at himself for the ridiculous double-entendre when he felt the stirrings.

Spock's cock began to vibrate in earnest, nearly thrashing inside of him, the girth expanding painfully quickly, forcing new pockets in the walls of his rectum to expand around the lubrication that had allowed Spock to reach the fully-extended state within Kirk's comparatively dry channel. Kirk's voice left him in a shout as dozens of nerves, never before stimulated by sexual activities, lit up as Spock's penis writhed within him, desperate to reach its peak, blindly seeking its own release in Kirk's so-very-accommodating body. 

Feeling Spock's penis stimulating every organ of his sexual and reproductive system _except_ his penis, Kirk let out a groan of frustration, worked one hand out from under his head and batted Spock's hand away and wrapped it around himself with a blissful sigh. Spock seemed to take that as his cue to let go completely. 

As Kirk gave happy, breathy little moans, finally getting his cock stimulated manually, Spock hissed, sounding more and more animalistic, positively alien as he clutched Kirk's body close to his and held on tight. His orgasm took them both by storm.

Ecstatically free from any mental reservations, Spock's penis finally opened every little pore and opening it had along its fully-extended length in anticipation of the final flood, which came slowly, in a heady wave that began in the very base of Spock's penis, where the holding-sheath had nearly turned itself inside out, flattened against Kirk's ass, and moved slowly, inexorably, up the white-green shaft, hot white fluid bursting from every pore as the girth increased to compensate, swelling to four inches in a ball shape that rushed up the entire length of Spock's dick, losing steam, emptying its payload as it went, until it finally burst through the mostly-porous tip of Spock's penis, and the Vulcan himself ended his possessive growl with a near-scream. 

Kirk just shivered and gasped his way to orgasm, overcome by the truly alien sensations, and simultaneously comforted by the practiced jerking of his hand. 

So full now that fluid was indeed starting to leak from his ass, Kirk sensed the immediate shriveling of his partner's organ, which had begun from the base as the moving ball-shaped cumload had swept its way up the shaft. Within seconds of his orgasm, Spock's penis had retracted fully back into its pouch, closed up safely away from the rest of the world. Jim panted and heaved for breath, which came more easily to him now that Spock had keeled over onto his side, allowing Jim's chest more room to expand. 

Puffing and gasping, Jim flapped one hand behind him to check that Spock was fully intact. His hand came into contact with the fully-closed and fully-shrunken sac, and also the ridiculous amount of fluid currently pulsing out of his ass with every breath. Clearly, having been stretched beyond his limit for so long and so far, his anus was not having any of this 'do-my-actual-job' business, and had decided to go as slack and lazy as the rest of Kirk. He was fleetingly grateful that Spock had had them both pee before starting this, since he probably would have wet the bed even more at this point. Half-groaning, half-laughing at his body's inability to perform any basic maintenance function beyond breathing, Kirk didn't even try to move beyond pulling his hand back over his side of his hips. 

Misinterpreting the sound, Spock weakly moved his hand over Kirk's backside, probing his anus for injury or blood. 

"I'm...okay, Spock. Not...bleeding...Or hurt," Kirk gasped out. 

Only half-reassured by that response, Spock whispered back, "Then you...would not mind if I...check...for...myself?" 

"Hmm?" was the only response Kirk gave before Spock's long, slim fingers were burrowing their way into Kirk's well-used and overly-slick asshole. 

Murmuring vague remonstrations and protests, Kirk dropped his head against his pillow and let Spock fiddle with him. The Vulcan had gotten a whole hand inside him and had shoved into Kirk's ass halfway to his elbow before he was truly satisfied that Kirk was not hurt by the whole ordeal.

"Damn!" Kirk proclaimed, heart still pounding, breath coming easier, but experiencing a bone-deep weariness only a Spock-sex-induced nap would cure, "that was...damn. I hope we never do that again.... at least for two hours." 

Spock froze briefly, then chuckled lowly against Kirk's ear. "We have nowhere to be and nothing to do for that amount of time, my Captain. Since you are weary, we shall sleep. And then it will be time for round two, as you would say."

"Goddamn," Kirk proclaimed with no further explanation. "How'd I get myself saddled with _this_!?" He very ineffectually slapped at Spock's hip, missing his ass, and the intended spank, by several inches.

The corners of Spock's lips pulled up, completely beyond his control, into an unmistakable smile, which he immediately hid against Jim's neck. With a supreme effort of will, he threw his nearest arm over Jim's torso and impusively hugged him. "Always by choice, _ashayam_. Always by choice."

THE END


End file.
